Many types of valves have been used in the past to provide an effective means for achieving a shut-off position by sensing the pressure of flow of fluid. The present invention does not sense the presence of movement of fluid, instead, it automatically closes if a fire hydrant, control valve or the like, attached thereto, is physically damaged. The breaking of the adjacent device may occur when it is hit by a motor vehicle or jarred by a natural physical force such as an earthquake, storm, avalanche etc. Prior art historically relied upon the fluid within the pipe for an indication of a leak of breakage which by the very nature of the dynamic physical attribute is complex and costly.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention, however the following U.S. patents are considered related:
______________________________________ U.S. Pat. No. INVENTOR ISSUED ______________________________________ 4,880,030 Terry 14 November 1989 4,792,113 Eidsmore 20 December 1988 4,665,932 Quenin 19 May 1987 4,522,229 Van de Moortele 11 June 1985 4,180,088 Mallett 25 December 1979 3,805,673 Fisher 23 April 1974 3,298,390 de Graff 17 January 1967 3,183,928 Rosenberg 18 May 1965 3,079,938 McCann 5 March 1963 2,943,636 Reed, et al 5 July 1960 ______________________________________
Terry in U.S. Pat. No. 4,880,030 teaches a water valve with capability of manually shutting off the water flow and also as a safety control device to sense excessive pressure wherein the water pressure will overcome the force exerted by a spring and force a piston against a flange blocking apertures thus stopping the flow of water.
U.S. Pat. No. 4,792,113 issued to Edismore utilizes a flow limit valve providing sharp valve closure at a limiting flow rate using a piston and a pair of magnets moving a pin with one magnet outside and the other inside the valve body.
Excessive velocity of a fluid is sensed by static and total pressure which in turn electrically controls the movement of a rod to actuate the safety valve U.S. Pat. No. 4,665,932 of Quenin.
Van de Moortele in U.S. Pat. No. 4,522,229 discloses a valve that cuts off water supply at a predetermined maximum flow and automatically returns to its initial position when reduced flow is present. This is accomplished by a flow regulator with a diaphragm in a precontrol chamber measuring flow and shutting off the flow from the discharge chamber.
U.S. Pat. No. 4,180,088 of Mallett utilizes an electrical circuit with a flow sensor turning off a valve when a leak occurs.
U.S. Pat. No. 3,183,928 issued to Rosenberg relates to a shut-off valve intended to control a feed line conduit through which a fluid flows, automatically shutting off when upstream pressure drops below a minimum value. This shut-off is accomplished by a spring loaded arm actuating a cock when insufficient pressure is available to retain its open position,
Reed et al in U.S. Pat. No. 2,943,636 discloses a hydrant fueling valve for fueling and defueling aircraft, operated by pressure of the fluid flowing through the valve regardless of the direction. A pilot valve and piston are utilized.
For background purposes and as indicative of the art to which the invention relates reference may be made to the Patents issued to Fisher and McCann.
From the above described prior art, it is seen that the use of a breakable spring loaded mechanism to close a valve in the event of physical damage is clearly lacking.